524 , PYKENULACEAE. 



continuus laevigatus, olim spermagoniis nigropunetatus. Gonidia chroolepoidea. 

 Peritheeia 1.0-1.5 mm. lata, solitaria aut confluentia dimidiata, primum im- 

 mersa leviter oonvexa dein emergentia elevata conieo-hemispliaerica, basi innata, 

 nigra sat tenue thallino sufEusa aut denudata, apice obtuso aut crasso papil- 

 late, demum elabentia foveolamque relinquentia, amphithecio carbonaeeo basi 

 defieienti. Paraphyses persistentes tenues simpliees. Asei oylindriees 8-spori. 

 Sporae in ascis uniseriales, incolores ellipsoideae, 4-loculares loeulis subcylin- 

 drieis angulis sat rotundatis, 13-16 X 5-7 .a. Spermagonia medioeria nigra 

 apice emergeute denudato. Spermatia filiformia arcuata, 18-22 X Im. 



On limestone, Key "View Hill, Vivijagua, Isle of Pines, Cuba (Britton, Britton 

 and Wilson, February 28-20, 1916, 15090, type). 



Bahamas: on limestone, Coclsburn Town, Watling's Island (Britton and Mills- 

 paugh, emi). 



Known also from two otber stations in the Isle of Pines and from one station 

 in Porto Rico. 



The affinities of this sriecies seem on the whole to be with the genus Porina, 

 section Sagedia^ although it has peculiarities which make its systematic position 

 somewhat uncertain. While the peritheeia are for the most part solitary, they 

 occur occasionally completely confluent, except for the papillate tips. Even in thfese 

 cases, however, there is never any indication of a stroma. The cells of the quadri- 

 locular spores are somewhat more rounded than is typical for Porina. There is no 

 other species with which this is liable to be confused. 



3. Porina firmula Muell. Arg. Bot. Jahrb. 6: 401. 1885. 



On limestone, Andros, at Mastic Point, and Watling's Island, near Coclibum 

 Tovm : — Cuba ; Isle of Pines. 



4. Porina subfirmula Eiddle, sp. nov. 



Thallus epilithicus determinatus subfoliosus effiguratus, irregulariter ro- 

 tundatus, margine iutegro aut erenato baud lobato, planus, arete adnatus, cras- 

 sus (crassitudine 0.15-0.2 mm.), atro-olivaceus, continuus laevigatus vel sat 

 inaequalis nitidulus; superne corticatus cortice tenue (crassitudine 12-14 /i) 

 pseudo-parenchymatica, inferne ecorticatus. Gonidia chroolepoidea. Peritheeia 

 subglobosa circ. 0.3 mm. lata, tota immersa aut apieibus leviter emergentibus 

 et sat denudatis, amphitheeio superne nigro inferne deeolore. Paraphyses per- 

 sistentes simpliees. Asei 8-spori. Sporae incolores fusiformes, baud bene- 

 evolutae, 6-8-loculares, loeulis oylindrieis, cire. 25 X 4/i. 



On limestone. Sierra de las Casas, Isle of Fines, Cuba (Britton and Wilson, 

 March 22, 1916, 157^1, type). 



Bahamas : on limestone. New Providence (Brace, 9li87) . 



This species belongs to the section Segestria, and is evidently related to but 

 quite distinct from the preceding species. Both species are decidedly Endocarpon- 

 like in appearance. 



5. Porina nucula Ach. Syn. Licb. 112. 1814. 



On bark of Exotliea, New Providence, at Clifton : — widely distributed in trop- 

 ical regions of both hemispheres. 



6. Porina mastoidea (Aeb.) Mass. Eic. Licb. Crost. 191. 1852. 



Pyrenula mastoidea Aeb. Syn. Licb. 122. 1814. 

 Forina africana Muell. Arg. Linnaea 43: 41. 1880. 



On bark. Great Bahama : — widely distributed in tropical regions of both hemi- 

 spheres. 



The material represents a form with verrucose thallus and verrucae, and the 

 latter are somewhat constricted ; but the species is so variable that it is scarcely 

 worth while to give this form a name. 



7. Porina Tetracerae (Aob.) Muell. Arg. Bot. Jabrb. 6: 401. 1885. 



Verrucaria Tetracerae Aeb. Metb. Lieb. 121. 1803. 



On bark. New Providence, at Maidenhead Coppice : — widely distributed in trop- 

 ical regions of both hemispheres. 



8. Porina variegita Pee, Suppl. Essai Crypt. 75. 1837. 



On bark, Abaco, at Old Kerr's Point ; — Cuba ; Jamaica ; Porto Rico. 



